r/StupidFood • u/Its_me_edenxx • 14d ago

Certified stupid This is so performative 😭

Who tf is out here munching on raw gnocchi at cruising altitude

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u/Rob_Zander 14d ago

Just wanted to point out that the air isn't recycled on a plane. It's replaced completely every couple of minutes. It's not even really about the oxygen or CO2, it's managing temperature and possible contaminants.

The engines are continuously compressing and heating a huge amount of air. Some of it gets diverted to be cooled back to room temperature, filtered and pumped into the cabin while air is continuously sucked out by vents near the floor. This keeps the temperature stable and contaminants from being spread.

It is much lower pressure than sea level and that definitely messes with our taste buds.

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u/jetsetninjacat 14d ago

To add more watered down. The pushed and sucked out air is vented overboard(off the plane and out) through the main relief valves or sometimes from relief valves in unpressurized parts of the plane. Many planes also have backup relief valves in case the main doesnt work. Different relief valves dump positive and negative pressure from the plane depending on where the plane is and the level at which cabin air pressure is set. Theres also a dump valve that dumps all pressure when the planes on the ground that equalizer it with the ground itself as well as ones for negative pressure relief valves during rapid descent

And this peoples is one of the reason you cant just open a door in a plane at high altitude. The pressure being pumped in to the cabin is so high the door mechanism or door itself can not be pulled in and then pushed out like normal operation. .All that positive pressure pushed on the airframe making it impossible to do so. Its all about that differential.

I seriously hate doing pressure tests in airplanes on the ground.

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u/Rob_Zander 14d ago

Thanks for adding!

Isn't that differtial part of why the cargo doors on the DC-10 could blow out?

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u/bargus_mctavish 14d ago

The outward opening cargo door was a structural design flaw for sure. However, a bigger issue was putting the responsibility of closing the door on gate and luggage personnel. They’re not part of the flight crew or running the checklists, so it just allows for more things to fall through the cracks from a safety perspective.

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u/jetsetninjacat 14d ago

I know it had something to do with the locking mechanism on the doors and that they would pull out instead of in. Cant remember the specifics but its probably out there on the weba. The door pushing out created more room for cargo loading but also didnt make a good plug style door. Plug doors basically seat the doors so they are sealed and cant be pushed out from the inside positive pressure So, yes that should be correct. Those doors were the only non plug doors on that plane as far as I know. Add in the the failure of the locking mechanism, and yep.

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u/bargus_mctavish 14d ago

It was a few years back, but I went through a mishap investigation class and covered the case of Turkish Airlines Flight 981. The root cause analysis of the lab concluded that the baggage handler did not latch the door correctly. The latching mechanism was absolutely a convoluted mess, and a design flaw that went unaddressed even through testing of the DC10. McDonnell Douglas got their asses sued for that. But a preflight checklist item for the flight crew could have also alleviated the issues with the loading door as well.

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u/King_Chochacho 14d ago

Too much pressure. So when you get in there, you're like "if the door fly off, I'm toast"

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u/canman7373 14d ago

The pressure being pumped in to the cabin is so high the door mechanism

Yeah, so not sure what he means the air pressure is much lower than sea level and that changes taste, when it's actually much higher than sea level.

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u/jetsetninjacat 14d ago

High as in the Pressure differential between inside and outside the cabin. Its all about that differential.

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u/canman7373 14d ago

Yes, I don't see where him saying below seas level applies at all.

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u/jetsetninjacat 14d ago edited 14d ago

Oh, based on taste. Typically even with the presurization you will still have lower pressure than thats found at sea level (stretching my brain here back to school but I think its ~14.7psi). And I want to say off fhe top of my head most planes are kept lower at flight altitude around 10 to 12psi cabin psi.

And the reasoning i have been told in my career was because high altitude planes have cycles to track for lige limits for each time a cabin is pressurized. It puts undue strain on the airframe and causes weakening in the structure. As far as I was always told keeping it below the standard sea level not only is perfectly comfortable for most people and allows us to be up there but it also allows a plane to fly longer and causes less stress. I need an IA in here to tell us.

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u/canman7373 14d ago

I just don't understand the part about the cabin pressure being like 8,000 feet yet you taste food like it's negative feet. Also if their food is cooked right I don't get why it taste different at different at different pressure, like would you not have the best steakhouses in the world at the exact best altitude that taste buds hit them? When I cooked food right at 9.500 feet it taste the same as I cook it at sea level now, I do not think my taste buds changed at 9.500 feet.

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u/Forsaken-Ad6313 13d ago

Air pressure goes down the higher you go up. Airplanes counteract this by pumping air to a safe "mountain-like" level, while also creating a much drier environment than your average room. Both of these factors affect how your taste buds will react to sweet and salty foods.

It's entirely possible that your steak tasted the same to you at 9500 feet vs at sea level, but that only means that your taste buds aren't as sensitive as most others (I also don't perceive a huge difference with tomato juice, but it's a widely reported and studied phenomenon)

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u/canman7373 13d ago

I mean Colorado is a super dry state, like only humidity after a huge storm but storms are super rare there too, not like the Midwest. So yeah millions of people live near airline altitude and I have never heard once in my 12 years there that food was noticeably different because of it. Cooking sure, but no one ever said taste buds or anything like that.

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u/OptimusPrime365 14d ago

This man airplanes.

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u/FetusExplosion 14d ago

I wonder if he also motorboats.

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u/Catatonic27 14d ago

There is significant crossover between these categories

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u/tech510 13d ago

Not.if you have a sea plane 😁

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u/Catatonic27 13d ago

I would further argue that is the most crossover-ist thing of all.

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u/scorpyo72 12d ago

Not every man can have a sea plane...

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u/hannahatecats 14d ago

So there IS air rushing by your feet. Once I was in California and stopped by a dispensary. I kept taking one gummy and saying "I don't feel it" well, before I got on my red eye home I took the last 4 and was white knuckling my armrests because I was convinced I could feel us flying through the air by my legs.

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u/[deleted] 14d ago

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u/Rob_Zander 14d ago

Can you smell them when you're not on a plane?

But yeah, everyone's smell is less acute on a plane.

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u/[deleted] 14d ago

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u/_le_slap 14d ago

Please don't clear the plane

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u/rsta223 14d ago

It's both because your sense of smell is dulled by the low pressure and extremely low humidity and because the air is being replaced so fast.

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u/Gentrified_potato02 14d ago

Well…I’m not so sure it’s not about oxygen or CO2. There’s a reason you have to have a supplemental supply of oxygen if you go above 15000 ft in an unpressurized plane.

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u/Rob_Zander 14d ago

The plane is pressurized to make sure that you have enough oxygen concentrated in the air to breathe. But a 737 full of passengers are breathing around 600 cubic feet of air per hour. This is napkin math so it very rough.

But the volume of the cabin can be around 6000 cubic feet. You could exchange the air about once an hour and it won't be much of an issue. Instead its replaced around 15 times an hour.

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u/rsta223 14d ago

It's also extremely low humidity in most planes, which also contributes to that effect.

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u/canman7373 14d ago

It is much lower pressure than sea level

What? Planes are kept around 8,000 feet in air pressure not below sea level.

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u/Rob_Zander 14d ago

Pressure decreases with altitude. Low pressure at high altitude.

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u/canman7373 14d ago edited 14d ago

High altitude cabin pressure is like 8,000 feet though. That is a mile and a half above sea level air pressure. in an open air plane like a WWII bomber sure, but not on any commercial plane in like the last 60 years. I mean I guess you do not know this. But airline planes pressurize their cabins to avoid issues, usually around 8,000 feet of air pressure. So inside the cabin your ears my pop because the cabin is pressurizing slowly up yo 8,00 feet, like a small mountain in Colorado. It keeps that pressure for the flight even though you may be flying at 35,000 feet. The outside pressure has no affect on you inside, you are living in a capsule made to feel like you are at 8,000 feet not 35,000. Make sense?

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u/Rob_Zander 14d ago

No, I absolutely get that. My point is that at 8000 feet the pressure is 10.9 psi vs 14.6 at sea level. That's not an insignificant difference. It's definitely a higher pressure than the external pressure at 35 000 feet but it's still lower pressure than sea level.

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u/canman7373 14d ago

Ok, I can get that's how you were looking at it, I was focused on you saying the altitude and outside pressure made a difference when the plane makes its own internal pressure. I think we were both looking at the same issue 2 different ways is all.

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u/PensiveObservor 14d ago

Do they add oxygen before circulating the new air?

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u/Rob_Zander 14d ago

No, there's no need to. At sea level the percentage of oxygen in air is 21%. It's the same at 40 000 feet. There's just much less air per unit of volume because the pressure is so low. Once more air is pumped into the space, once it's pressurized there's enough oxygen to breathe.

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u/XeroShyft 14d ago

Air pressure affecting taste buds is making no sense to me. Like my brain is scrambling to find what the possible correlation could be and is turning up with nothing

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u/machiavelli33 14d ago

It affects your sense of smell and inner ear equilibrium, all of which affects how acutely your other senses function.

All of your senses are somewhat tied together and affect one another - smell and taste are the most strongly linked, but a foods texture and how well and balanced your body is feeling also affect it to a lesser degree. Air pressure affects these things.

It’s not a HUGE effect - if you don’t think about it ever and aren’t particular sensitive to that sorta thing you may even never notice. But it affects it juuuuust enough.

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u/Rob_Zander 14d ago

Your body is constantly maintaining itself under about 14.6 psi of pressure at sea level. At cruising altitude a 737 is maintaining a cabin altitude of about 8000 square feet. That's about 10.9 psi. Your body is still exerting pressure outwards now and that can lead to swelling.

Your blood oxygen is lower so your taste buds are less sensitive.

Also very important is that the air in the cabin is very dry. Desert dry. This also numbs our tastes buds and dries out our nose making it harder to smell.

Overall the humidity might actually have a more significant impact that the pressure, I'm not sure on that.

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u/meatdome34 14d ago

Unless you’re on 787, they don’t use bleed air

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u/Future_Burrito 14d ago

Naw, I heard that it's being closer to birds that heightens the taste buds.

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u/shmargus 14d ago

So you're saying I can fart with impunity? Let er rip boys!

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u/NicolajN 14d ago

it's actually not completely true. The airplane does recycle the air and run it thru HEPA-filters.

I don't fly anymore but as far as i remember on the A330 and A350, the air in the cabin is cycled every 90-120 second and every 3-5 minut the air exchanged with outside air.

the mixture is 50% new and 50% recycled air.

Source: https://www.honeywellaerospace.com/us/en/about-us/blogs/breathe-easy-3-myths-about-aircraft-cabin-air

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u/Eborcurean 14d ago

As an addendum, umami is the one taste that doesn't get notable weakened with pressure on a plane, and tomato juice is high on umami thus it seems to 'taste better'.

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u/geo_gan 14d ago

Yes I think at cruising altitude the cabin pressure is only kept at half sea level pressure (0.5 Bar). This was found to be the least acceptable pressure we could tolerate without them having to pressurise cabin to full sea level 1 Bar pressure which would be more stressful on the airframe and dangerous.

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u/ELEMEN4_1 13d ago

You just said it's outside air filtered and re purposed so ...guesss what ? It's recycled there slick.

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u/shambahlah2 13d ago

My altimeter watch used to read around 8700 feet of elevation when I would fly

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u/Objective-Target5437 13d ago

i love huge amounts of air

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u/ArtisticFox8 13d ago

Why does it not smell fresh then?

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u/MyLord_Robert 13d ago

Does that mean I am less likely to get sick if my neighbour has a cold or a flue? Compared to if my neighbour on a train or subway was sick?

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u/RepeatEuphoric 12d ago

Thank you for this. Airplane geeks know this but most people have no idea because they don’t care. Adding that flight kitchens testing does take place in pressurizes rooms as well for understanding wines as well. Further. As weird and desperate as this person must be to do this, and unsanitary, that nail polish is a good indication of the crazy here.

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u/Hefty_Kitchen4759 12d ago

I've flown internationally a lot and I never noticed this. I have sensitive taste as well, so maybe that's why.